A rotary damper disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-81482 (Patent reference 1) is known as a rotary damper comprising: a partition wall that partitions a space formed between a rotor and a housing for housing the rotor and forms a fluid chamber filled with fluid; and a vane provided in the fluid chamber.
A rotary damper of this kind can slow down the rotational motion of an object to be controlled by resistance caused when fluid pressed by a vane swinging in a fluid chamber moves through a small gap or the like between the vane and a housing.
However, in the conventional rotary damper, the partition wall is formed integrally with the housing but a casting method such as zinc die casting or the like is used as forming means. For this reason, the conventional rotary damper presents the problem of increasing manufacturing cost and has the defect of increasing the weight of a product.
Moreover, the shape and size of a flange used when the rotary damper is mounted is designed in accordance with an object having the rotary damper mounted thereon. However, because the flange is provided for the housing, the die of the whole housing including the flange needs to be manufactured every time design is changed.
Furthermore, in a rotary damper having a plug bonded thereto by caulking the edge of the opening of the housing formed by zinc die casting, there is presented a problem that a caulked portion is easily deformed by creep caused by internal pressure.
[Patent Reference 1] Japanese Patent Application Laid-Open No. 2002-81482